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A113304 Primes that divide some central trinomial coefficient, A002426. 4
3, 7, 17, 19, 41, 43, 47, 73, 107, 109, 113, 131, 173, 179, 191, 193, 199, 233, 269, 277, 281, 283, 293, 307, 311, 347, 373, 383, 401, 409, 419, 421, 439, 443, 457, 467, 503, 509, 521, 547, 563, 569, 593, 613, 617, 631, 653, 673, 691, 701, 709, 719, 739, 743 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For primes less than 10^6, the density of these primes is near 0.3925.

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..1100

MATHEMATICA

nn=1000; a=b=1; t=Join[{1}, Table[c=((2n-1)b+3(n-1)a)/n; a=b; b=c; c, {n, 2, nn}]]; pLst={}; Do[p=Prime[n]; k=1; While[k<p && Mod[t[[k]], p]>0, k++ ]; If[k<p, AppendTo[pLst, p]], {n, PrimePi[nn]}]; pLst

CROSSREFS

Cf. A113302 (number of k for which prime(n) divides T(k)), A113303 (least k such that prime(n) divides T(k)).

Sequence in context: A076194 A167168 A064699 * A194945 A093651 A181420

Adjacent sequences:  A113301 A113302 A113303 * A113305 A113306 A113307

KEYWORD

nonn

AUTHOR

T. D. Noe, Oct 24 2005

STATUS

approved

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Last modified February 23 17:23 EST 2018. Contains 299584 sequences. (Running on oeis4.)